You can't earn money with a PPL.
"no person who holds a private pilot certificate may act as pilot in command of an aircraft that is carrying passengers or property for compensation or hire; nor may that person, for compensation or hire, act as pilot in command of an aircraft"
The only exclusion on this is to be a Flight Instructor, but you still cannot be paid for this.
There are certain requirements for entering the course too, see below:
- Hold a valid pilots licence, which includes a valid Single Engine Piston (Land) rating
- Meet the knowledge requirements for the grant of a JAR CPL (A)
- Have at least a CPL (A) or have completed at least 200 hours of flight time of which 150 hours as Pilot-in-Command if holding a PPL (A)
- Have completed at least 30 hours on Single Engine Piston powered aeroplanes of which at least 5 hours shall be in the 6 months preceding the pre-entry flight test).
- Have completed at least 10 hours instrument flight instruction of which up to 5 may be in a simulator.
- Have completed 20 hours cross-country flight time as PIC of aeroplanes including a cross country flight of 540km (300nm) with full-stop landings at two other aerodromes.
- Passed a specific pre-entry flight test within the 6 months preceding the start of the course.
So you will need to build up some hours too beforehand.
Most schools apparently are happy to recruit graduates from their FI courses, how true that is I don't know but considering they would be working for free, I wouldn't be surprised by it.
Have a good think, if you are keen on getting your CPL and IR, maybe doing your CPL first is a good idea, before your FI rating, it contributes some hours and lets you earn $$$, not much though remember.